An IC chip electrically communicates with off-chip electronics to exchange information. The IC chip may employ a different voltages than are employed by off-chip electronics. Accordingly, the interface between the IC chip and off-chip electronics must accommodate the voltage differences. One such interface includes a mixed voltage input/output (“I/O”) driver as discussed in ESD Protection For Mixed-Voltage I/O Using NMOS Transistors Stacked In A Cascode Configuration, by Warren Anderson and Davis Krakauer and published in EOS/ESD Symposium 98-55, herein incorporated by reference. FIGS. 2 and 3 of this publication show an ESD protection structure including two NMOS transistors in a cascode configuration, where the transistors are merged into the same active area of a substrate. The two NMOS transistors allows a 5V signal to be dropped to 3.3V during normal operation while providing a parasitic lateral NPN bipolar transistor during electrostatic discharge. Under ESD conditions, the stacked transistors operate in snapback with the bipolar effect occurring between the source of the bottom NMOS transistor and drain of the top NMOS transistor. While this I/O driver has been used for some generic designs, it has been a continuing challenge to balance electrostatic discharge protection performance and I/O performance. Accordingly, it is desired to improve upon the performance of a cascode MOS driver. More specifically, there is a need to remove the ESD design constraints from drivers to achieve maximum I/O performance.